Talk:Electric car

References 32 and 33 are doubtful

The efficiency of a gasoline engine is about 16%, and 20% for a diesel engine.[32][33].

1. ^ Johnson, C (15 April 2009), Physics In an Automotive Engine, Public Service Projects at mb-soft.com, http://mb-soft.com/public2/engine.html, retrieved on 2009-04-25

This reference uses a 20MPG small block Chevrolet 350 V8 engine with only an 8 to 1 compression ratio. I had a Gas/Petrol car 25 years ago with a 10 to 1 compression ratio. CR is directly related to efficiency. Can you actually buy a modern car with a CR that low?

The US DOE and EPA rate modern TDI type engines at 44%, there is serious book cooking going on to rate it at 20%. In fact there is no specific reference to diesel engine efficiency at all in the 'Reference'. The gas engine efficiency similarly bears no relationship to US DOE / EPA figures. This reference is not credible and the statement it 'references' should be deleted.

I personally drive a 15 year old direct injection diesel Golf sized car, (rated by its makers as 38% efficient), that returns 55MPG (imperial), that is a world away from these fantasy figures. It has a 600 mile range on renewable fuel and can seat four with luggage.

85.119.112.132 (talk) 02:15, 8 July 2009 (UTC)

I have given up any attempt at fixing these calculations. The problem with your observation is that you are quoting peak efficiency, whereas a car very rarely runs at that particular speed and load. Greglocock (talk) 02:29, 8 July 2009 (UTC)

Comparing a 1970s gas/petrol powered car with current electric vehicle technology is not fair or reasonable, it is biased. Because diesel cars have higher torque generally than comparable gas/petrol cars, their efficiency is less impaired by urban driving conditions than gas/petrol. The effect of automatic idling shutdown systems (or even by turning the key! by law in Germany), six speed manual gearboxes and Continuously Variable Transmission should be considered, if a like for like comparison is to be made. CVTs allow engines to run at optimum efficiency. That is current conventional IC engined vehicle technology. According to a review of a Toyota petrol/gas hybrid SUV against against a Mercedes commonrail diesel SUV, in the UK 'What Diesel?' magazine, the diesel with a conventional five-speed gearbox was slightly more efficient. This would seem to indicate that the efficiency improvement of hybrid drive technology (which very similar to plug in electrics), is about the same as diesel over petrol, which is about 15%. This reference is claiming it to be much higher than that. Where are the diesel hybrids that use both technologies? Cooking the books with biased comparisons, and fishy figures is damaging to the push for reduced carbon emissions. Why not tell the truth and leave chicanery like this, to people like the car industry, who used a CO2 emission argument in the UK to get a government 'banger' (that all had to have a current certificate of roadworthiness) car scrappage scheme, with very fishy figures for CO2 emissions of car production vs lifetime emissions. 85.119.112.122 (talk) 16:54, 22 August 2009 (UTC)

To clarify: The MPG of the diesel SUV was slightly higher than the MPG of the hybrid SUV over the same testing, with vehicles of the same size. AFAIK the hybrid drivetrain is very similar to plug in electric cars. The grid efficiency of fossil powered electricity is about the same as that of a petrol engine in a hybrid. How can efficiencies so much higher than diesel powered cars be claimed for plug in electric cars in the light of this? Do the figures come from people who have a vested interest in electric cars? Perhaps it is no accident that when you try to compare the figures it is an apples and pears situation. 85.119.112.37 (talk) 23:52, 28 October 2009 (UTC)

Quote : "An accident in a 2,000 lb (900 kg) vehicle will on average cause about 50% more injuries to its occupants than a 3,000 lb (1,400 kg) vehicle"

This fails to mention what it means for the occupants in a vehicle that's been hit by a heavier vehicle as opposed to a lighter vehicle. I'd guess it's not good. F=ma last time I checked? —Preceding unsigned comment added by 86.0.4.150 (talk) 13:14, 11 July 2009 (UTC)

What does the reference for that remark say? oh. Greglocock (talk) 04:52, 14 July 2009 (UTC)

One has to question the quality of a reference from insurance.com! —Preceding unsigned comment added by 86.0.4.150 (talk) 01:02, 18 July 2009 (UTC) Are you claiming not WP:RS? If it is a fact it is a fact, and to my mind it doesn't matter too much where you get it from. However, if it is a blurb from a company, to emphasise their good deals on smaller or larger vehicles, I would say that is not RS. Can you qualify your objection? SimonTrew (talk) 11:10, 27 July 2009 (UTC)

I think the worst part about all of this is that there is a misconception that a heavier vehicle automatically is safer than a lighter vehicle. However, this doesn't address the issue of why the vehicle is heavier. Is the vehicle heavier because it has a large engine bay, lots of safety reinforcement all around or is it because some guy took a 1800lb CRX and strapped 12000lbs worth of gold into the trunk and passenger seat. Don't argue about whether or not someone would do such a thing, the point is, what percent of the weight of the vehicle is used to decelerate and the other percent that is BEING decelerated. Batteries are heavy and having 1000lbs worth of them means that's 1000lbs that can't be used towards the safety of the vehicle and if they're working within a weight constraint, then that means the vehicle is inherently less safe than another vehicle that doesn't have that constraint. --Imzjustplayin (talk) 22:56, 21 October 2009 (UTC)

Except that you are wrong. Do the physics. A Mini with 1000 lb of batteries hitting a Mini with no batteries will see lower accelerations. Greglocock (talk) 00:07, 22 October 2009 (UTC)

Lower accelerations or not, the accident is going to be worse if you have two minis with 1000lbs of batteries hitting each other than without those 1000lbs of batteries. You also seem to forget that while a disparity of accelerations can be an issue, there is going to be much more serious deformity in the cars when the weight isn't able to be used in the deceleration of the car. I wouldn't be surprised if you thought that two cars going 30mph weighing exactly the same, and crashing head on into each other would be the same as a one car going 60mph into a wall. Fact is, the accident will be worse for BOTH drivers, meaning that adding that 1000lbs of weight made the situation worse for that mini driver than had he not had it in the first place.

To quote the NHTSA using the very article that was used to backup the claim that heavier cars are safer..."

Momentum conservation: When a heavy and a light vehicle collide, the heavy vehicle keeps moving forward; its occupants experience a small velocity change. The light vehicle gets pushed backward; its occupants experience a higher velocity change. These are consequences of the laws of physics; nothing can be done to equalize the velocity changes. For example, in a head-on collision, a 1 percent weight advantage corresponds to more than a 5 percent reduction in the driver's fatality risk, relative to the driver of the other vehicle.

What benefits an individual – being in the heavier of the two vehicles – however, does not necessarily benefit society as a whole. Based on momentum considerations alone, the risk reduction in Vehicle 1 as it becomes heavier is cancelled by a risk increase in Vehicle 2. If momentum conservation were the only factor making heavier vehicles safer (it isn’t), overall fatalities in multivehicle crashes would neither increase nor decrease if the entire vehicle fleet were reduced in mass.

Crashworthiness: Heavier vehicles have historically done a better job cushioning their occupants in crashes. Their longer hoods and extra space in the occupant compartment provide an opportunity for a more gradual deceleration of the vehicle, and of the occupant within the vehicle. In the New Car Assessment Program, crash test results have been consistently better for large cars, given the same 35 mph barrier impact. While it is conceivable that light vehicles could be built with similarly long hoods and mild deceleration pulses, it would probably require major changes in materials and design and/or taking weight out of their engines, accessories, etc.

Structural integrity: Heavier vehicles have historically provided better protection against intrusion by fixed objects, heavy trucks, etc. Doors, frames, pillars, roof rails, etc. are thicker and stronger. Since the occupant compartment is larger, these structures also have more room to deform.

Mass mismatch: There is widespread belief that a collision between vehicles of similar mass is safer than a collision of badly mismatched vehicles. If so, making the heaviest vehicles lighter, and the lightest heavier, could reduce fatalities in crashes between passenger vehicles. (However, analyses in Section 6.6 of this report do not show significantly higher fatality rates per unit of exposure in crashes of 2,000 with 4,000 pound cars than in crashes of two 3,000 pound cars.)

--Imzjustplayin (talk) 08:33, 22 October 2009 (UTC)

Agreed. Now you appear to be writing more sensibly on the matter. Keep it up Greglocock (talk) 01:32, 23 October 2009 (UTC)

Well I guess one swallow doesn't make a summer and you've gone back to a distinctly unhelpful mode of editing. Greglocock (talk) 04:34, 9 November 2009 (UTC)

There is nothing to discuss as I already proved my point. You're unable to refute what I say yet you keep insisting on putting back that drivel, which is completely inaccurate. The batteries do NOT make the car any safer which is clearly pointed out by the very source that you and I are referencing. I added to the article sufficient information, and you decide to completely strip it of that and put back that garbage which is wholly inaccurate. We're not talking about SUVs or Supras crashing into Geo Metros, we're talking about light weight gasoline Geo Metros crashing into Heavy, Battery powered GEO metros carrying 1000lbs worth of batteries into each other. You can be assured that nobody is going to survive that crash because neither car is capable of dissipating the additional crash energy.--Imzjustplayin (talk) 23:56, 9 November 2009 (UTC)

You have proved nothing. A car with 1000 lb more of batteries in it hitting an identical car without the payload will see lower accelerations. Quit bluffing and accept the truth of that 400 year old statement. The refs support that statement Greglocock (talk) 11:07, 10 November 2009 (UTC)

The problem is you keep emphasizing accelerations yet what we're talking about is actually what is a safer situation. Let me write it again; "There is widespread belief that a collision between vehicles of similar mass is safer than a collision of badly mismatched vehicles. If so, making the heaviest vehicles lighter, and the lightest heavier, could reduce fatalities in crashes between passenger vehicles. (However, analyses in Section 6.6 of this report do not show significantly higher fatality rates per unit of exposure in crashes of 2,000 with 4,000 pound cars than in crashes of two 3,000 pound cars.)" (From the NHTSA report). So while the heavier vehicle may see lower accelerations (which you seem to have been so caught up on) the crash is overall more deadly. It's not the weight mismatch that is the issue, it's the whole energy equation, that when you add more weight, especially into vehicles that aren't designed for that additional weight, you end up with a much less safe crash. A car with four passengers is going to receive a lower crash test rating than a car with a single passenger. I think the most bothersome thing about all of this is that you revert my edits and have the article go back and state that those heavy batteries make the car safer when it in fact does not and actually does the opposite. The NHTSA article you reference backs up everything I say and while it won't say what you say about accelerations is wrong, what it will say which is what you've effectively said is that heavier cars makes for more deadly crashes especially if the weight isn't able to be utilized in the dissipation of crash energy. Maybe you want some reassurance, here I'll give it to you, you are right, the heavier Geo will see lower accelerations than the lighter one. With that said, a weighted down car does not make a safer car.--Imzjustplayin (talk) 05:32, 14 November 2009 (UTC)

What we are talking about specifically is the fallacy that adding batteries to a car will make it more dangerous. So far as the occupants of that car are concerned that is untrue, for good fundamental reasons, which you now seem to agree with. I agree that for the other car in a two car collision it'll be worse. I have reverted your deletion yet again, and added a sentence that discusses the negatives. Why not spend some time EDITING that section instead of deleting it? Also do not delete the part about LRR tires. Greglocock (talk) 06:05, 14 November 2009 (UTC)

It's better to receive higher accelerations if it means that you aren't crumpled to death which is what very well would happen if you added 1000lbs worth of batteries to a Geo metro which isn't even considering the weight of the passengers themselves. An 1800lbs geo metro crashing into a Camry will be safer for the passenegers than a 2800lbs Geo Metro crashing into the same Camry because the heavier Geo Metro while experiencing less accelerations will have devastating crumpling of the passenger safety space, making accelerations completely irrelevant. --Imzjustplayin (talk) 07:00, 14 November 2009 (UTC)

If you recently reverted my edits using an IP then you are playing a rather silly game. I have moved LRR to a separate section. I am afraid you are wrong, adding batteries to the Geo will reduce the accelerations it sees, and will reduce the severity of the accident for its occupants. Not so for the guys in the Camry. I suggest you build a simple analytical model of two crashing cars and use the known laws of physics to validate my comments. Greglocock (talk) 07:44, 14 November 2009 (UTC)

I don't know what's wrong with the people at wikipedia, either they're incapable of actually reading your references or they're too busy trying to make the articles look like they have as much data as possible, but the fact is, not only is your post about a heavier car sustaining less damage irrelevant but it's factually inaccurate when it pertains to a car that had the weight added to it after the fact and not when it was designed with it. You know absolutely nothing about crash testing if you think that you can just add weight to a car and not suffer serious negative consequences in doing so. Where does this additional energy go? Huh? When you crash a car, the energy is dissipated by crumpling of the car, when you add more energy to a crash situation you're either going to get more crumpling. If you had seen the crash tests of a Geo Metro into a wall, you can see the vehicle can barely prevent itself from crushing its passengers. When you add more weight, how can you expect anything but more crumpling of the safety space which in the case of a Geo Metro could mean life and death (the car already does poorly enough as it is). You and the other wikipedians seem to be incapable of understanding this, what exactly do I need to give you to stop reverting my edits and the edits of others that contradicts what you feel should be posted? Do I need a representative at the NHTSA to write you an e-mail, explaining to you why you're wrong or is this crap just going to continue ad-nauseum because you can't bare to find out that you're actually wrong and the very article you reference proves my point...--Imzjustplayin (talk) 18:50, 14 November 2009 (UTC)

You don't seem to have a very good handle on the physics. The energy goes into the other car (to use your terminology). As I suggested before, build a simple model, using Newton's laws. You are absolutely right, in 30 years of automotive engineering I have never worked directly for crash. I do however work out dynamic loads for them if their sensors fail or they don't measure something important, and investigate specific mechanical problems that they run into. Can I ask how much experience you have with crash, or indeed physics? Just for grins I set up a Monte Carlo simulation of a population of heavy cars, with a variable crush zone, smashing into a population of lighter cars, with variable crush zones. The results were banal. You always want to be in the heavier car, no matter what crush zone you, or the other car, have. Your main problem with Wikipedians is that you keep deleting stuff instead of editing it. You even deleted a sentence that specifically mentioned your point. How dumb is that? Greglocock (talk) 21:34, 14 November 2009 (UTC)

One thing to keep in mind in all this - the acceleration each vehicle suffers is in changing from its initial velocity to the velocity of the center of mass of the combined two vehicles. If you add mass to vehicle A, then the velocity of the center of mass changes, lessening its velocity change during the collision. That explains some of the physics disagreement here.

If you're running into a solid wall or pole, the center of mass is only the center of mass of vehicle A, so there's no change to the dynamics from weight changes (but the energy does change, with total M...). If you hit a much heavier vehicle, the center of mass velocity change also is minimal. So adding some weight to an otherwise structurally identical light car does make some collisions worse, certainly. Georgewilliamherbert (talk) 00:28, 15 November 2009 (UTC)

Can we stop the nonsense about accelerations not being indicative of crash severity? Bothte EEC and NHTSA use accelerations, here's a couple off the web. Here's the allowable sled pulse for a belted occupant in the EEC I think

http://www.dft.gov.uk/transportforyou/access/tipws/coll_thesafetyofwheelchairoccupa/dft_mobility_022736-1.gif

head pulse here from nhtsa

http://www.nhtsa.dot.gov/cars/rules/rulings/HeadRest/Index.html

Google is your friend , corridor is the term. Greglocock (talk) 07:29, 15 November 2009 (UTC)

LRR tires

I'm deleting your bit about the LRR tires because they do NOT necessarily have worse braking performance compared to some of the cheap OEM tires that many cars are equipped with. Some tires aren't LRR at all, have poor tread wear rating, braking performance, handling performance and in a sense poor everything except price. There are a lot more factors into what makes a tire a tire. You can have an LRR tire outperform and high performance tire, it's not an impossibility. We will not know definitively whether or not a particular tire is truly an LRR and has good performance until the Feds finalize the rating standards for LRR tires this December.--Imzjustplayin (talk) 07:00, 14 November 2009 (UTC)

The sentence on LRR tires is supported by a reference. I also have, but cannot publish, a chart showing the rolling resistance of about 100 different tires and their peak braking force at nominal load and pressure. As you might expect, the data is noisy. But the trend is as you would expect - more grip costs you more rolling resistance. The upper limit of performance forms a nice straight line. The reason is fairly obvious - the same property of the compound that improves adhesion also increases its damping, hence its rolling resistance. That is not to say you can't have LRR and good mu, but it will be a more expensive tire, and may involve other compromises. Yes Virginia, I did used to be a tire design engineer. Greglocock (talk) 07:44, 14 November 2009 (UTC)

Article semiprotected for 3 days

Due to the back and forth edit warring, I have semiprotected for 3 days. I have also asked the IP editor to discuss the safety issues here on the talk page.

Other editors, please do not use the semiprotection as an excuse to avoid open and good faith discussions on the issue the anonymous IP has raised. Remember we assume good faith about all contributors. Thanks! Georgewilliamherbert (talk)

Problems

"Lead-acid batteries are the most available and inexpensive and can be charged and controlled with low cost equipment, although owing to relatively short lifetime, due to high discharge rates and deep-cycling which they are unsuited for, have a higher overall cost than more expensive alternatives."

There are deep cycle lead acid batteries, so the statement is wrong as well as enigmatic (nowhere in the article is deep cycling defined). Lead acid batteries have a much lower overall cost than any other form of battery, this is indisputable. This is so wrong I have changed the section. 203.26.122.12 (talk) 03:44, 1 December 2009 (UTC)

"Charging time is limited primarily by the capacity of the grid connection."

In most cases, it is limited by the speed at which the battery can be recharged, not the supply.

 --> No, as long as the battery can be kept sufficiently cool, the rate at which the battery can be recharged is dependent on power availability. You can charge a very large battery in a very short length of time given enough power and a method to dissipate waste heat.  —Preceding unsigned comment added by 130.76.64.17 (talk) 18:01, 10 December 2009 (UTC) 

" A normal household outlet is between 1.5 kW (in the US, Canada, Japan, and other countries with 110 volt supply) to 3 kW (in countries with 220/240V supply)."

The "capacity" which you seem to be referring to here, is the power output. Now, P = IV Power (W) = Current (A) x Voltage (V)

for a 240V system on a standard 10 Amp wall outlet: P = 10 x 240 = 2 400 W (2.4kW) for a 110V system on a standard 10 Amp wall outlet : = 10 x 110 = 1 100 W (1.1 kW)

However, the relevant figure is Kwh(kilowatt-hours), not power(kW), in order to calculate the charging time. (BTW, households in countries with 110V power outlets have access to 220V at the meter). The article also says nothing about 3 phase power, which will reduce charging time.

This section needs to be rewritten by someone with a better understanding of electricity. —Preceding unsigned comment added by 203.26.122.12 (talk) 04:11, 1 December 2009 (UTC)

300W electric car heater

The citation for the 300W electric car heater in the energy efficiency section appears to be advertising/spam. The product is not designed for use in electric cars and the source website does not show that a 300W electric heater is the proper size for an otherwise unheated vehicle. The heater shown is for supplemental heat in the backside of a gas or diesel fuel car. —Preceding unsigned comment added by 130.76.32.182 (talk) 17:59, 10 December 2009 (UTC)

íTake it out then. WP:BOLD Si Trew (talk) 20:12, 10 December 2009 (UTC)

Protest here, That wasn't intended as spam, and the link states that the product is used in cars, now 300 Watt is not enough in cold climates, a 1kw or 2kw heater would do, "The cabin heater also draws a fair bit of power (1500 watts),"[www.teslamotorsclub.com/faq.php], and a 25% range reduction [1]. Mion (talk) 21:34, 10 December 2009 (UTC)

That's a much better quote than what is in the article. The 300W unit is not for EVs, and wouldn't even get the frost off a windscreen. Greglocock (talk) 04:52, 11 December 2009 (UTC)

Efficiency Comparisons are Misleading -- need Apples to Apples

The discussion of efficiency talks about power transmission and generation costs for electricity (which are perfectly legitimate) but neglects to discuss the efficiency of fossil fuel production and distribution. I've seen "guesstimates" of 50% (i.e. one gallon of fuel is needed to produce and distribute one gallon of fuel) which seems ridiculously high, but massively modifies the equation no matter what the figure is.

In short -- well-to-wheel needs to be broken down into well-to-car and car-to-wheel and the two figures compared fairly. —Preceding unsigned comment added by 206.113.178.218 (talk) 16:48, 14 December 2009 (UTC)

Yes that is ridiculously high. A more common figure is 83-87% of the energy in the well gets to the tank. There are many problems you will run into when performing this calculation, terrible tho that section is, it is the best compromise we could achieve. Make sure all the figures you use are from a believable source, and that the algorithm and assumptions you use is not WP:OR. in particular any claim that you will be able to magically use renewable energy alone (or natural gas) to recharge your batteries will be laughed out of court. Use real present day or recent values. Oh and get a username.Greglocock (talk) 05:41, 15 December 2009 (UTC)

No one needs to get a username if he/she would prefer not to. There are many reasons why some people might prefer anonymity. We need to edit based on the quality of their input rather than whether or not they choose to adopt a username. In the past, I've been admonished by admins for suggesting that contributors would be taken more seriously if they signed up for usernames.Fbagatelleblack (talk) 21:48, 15 December 2009 (UTC)

True. But your edits ARE far more likely to be taken seriosuly if you have a username, whatever ideals admins may have.Greglocock (talk) 05:57, 16 December 2009 (UTC)

The explanation that diesel and gasoline powered cars use heat engines to produce work while EV's use chemical energy to produce work should be removed; internal combustion engines aren't heat engines. —Preceding unsigned comment added by Kram-bc (talk • contribs) 08:47, 23 January 2010 (UTC)

Israeli site

This Israeli site: [EC] has an article about this subject.Agre22 (talk) 00:17, 24 December 2009 (UTC)agre22

The electric car revolution starts in Israel

This Israeli site: [Haaretz] tells that the electric car revolution starts in Israel.Agre22 (talk) 21:44, 31 January 2010 (UTC)agre22